Three way catalytic (TWC) converters are employed in gasoline powered internal combustion engines to reduce the level of environmentally toxic hydrocarbon (HC), carbon monoxide, and nitrogen oxide gases in the exhaust. The TWC converters perform the tasks of reducing nitrogen oxides to nitrogen and water, and oxidizing carbon monoxide and HC to carbon dioxide, and carbon dioxide and water, respectively. TWC converters operate most effectively when the engine is operated within a narrow range of air-fuel ratios (AFR), and engines are typically cycled between excess fuel, “rich” AFR conditions, and excess oxygen “lean” AFR conditions. Oxygen storage materials, such as cerium oxide, are utilized in TWC converters to store and release oxygen as the engine is cycled between lean and rich operating conditions. Ceria, in combination with platinum group metals (PGM), have been used in materials for storage and release of oxygen to improve conversion performance of TWC under cycled AFR conditions. However, cerium is a rare earth element whose supply is variable, and it's price and availability may be subject to wide price fluctuations.
Accordingly, alternative oxygen storage materials would be useful to replace ceria based materials currently in use.